Elizabeth Levy presents a punchy perspective on the past with two new titles in America's Horrible Histories series, Awesome Ancient Ancestors! and Who Are You Calling a Woolly Mammoth?, both illus. by Daniel McFeeley. Chunky blocks of informative text, timelines, sidebars, cheeky chapter headings (""Hello, People! Good-bye, Mammoths""; ""A Huntin' and Gatherin' We Will Go""; and, for Mammoth, ""The Ice Age Cometh"") and a wisecracking cockroach guide lead readers on an informative exploration. (Sept.)